Determination of algal biomass with HPLC pigment analysis from lakes of different trophic state in comparison to microscopically measured biomass

A high-performance liquid chromatography (HPLC) method is presented with which a direct determination of the phytoplankton biomass is possible. By correlating over 100 samples investigated with HPLC as well as microscopically, it has been shown that phytoplankton biomass is described very accurately by determining the concentration of accessory pigments. In contrast to earlier studies, we made a direct correlation of marker pigments with biovolume and did not consider the ratio of marker pigment to chlorophyll a. Determination of the dominating class in each lake succeeded with con-elation coefficients > 0.90, and even 0.96 against total biovolume. Because of the large number of samples, statistical proof indicates that algal marker pigments are better indicators for phytoplankton biomass than chlorophyll a. This HPLC method is ideal for large-scale monitoring because of its suitability for routine analysis and its extensive sample throughput. The procedure is applicable to different natural waters, from oligotrophic to highly eutrophic. Because of the simultaneously performed analysis of chlorophyll a, the succession of existing data is ensured.